iCE

got a 94 z28 6-speed w/ 110k. The car has been pampered through the years. It was not even driven from 96-00. Anyways, when I hit the gas it goes strong as could be but as soon as I hit around 4,500 - 5,000 rpm the engine cuts out for 1/4 of a second then kicks in again. sometimes it will cut out a couple times before I max the redline. This is really killing my et's.

I am guessing it could be either a: plugs/wires (I have not changed them yet)
or b: fuel injectors (crap I hope not)

what do you LT1 guros think???? shoebox or frez prolly knows.......

madwolf

Your opti is also a possibility, although the typical cut outs I've seen are around 5200.

whitedakota

im in the same boat as you...i have a 95 Z with 86,000 on it and i have a couple of mods done to it, mine runs strong when the engine is cool, then when it gets about 200* it has that high rpm stumble or miss..usually about 4500-6000!

i cleaned my iat, and maf and it helped a little and also replaced plugs and plug wires...still does it.

most people say its a sign of a failing opti.

no clue,
steve

GREGG 97Z

If they are the original plugs and wires I would try replacing them first. If not thats not it I would try a new fuel filter and check the fuel pressure, possibly a new coil.

killerkelly95

Dude I think its ur fuel injectors you might wanna check thoses out first, you never know it could be something else too just check everything maybe replace some caps and stuff then see what happens

MJ_Z28

I had that very same problem. I ordered new coil, coil wire, plugs and wires. As soon as I got the package I put the coil and coil wire in...problem was gone. I attributed it to the white buildup you get between the coil and the coil wire as it would likely act as an insulator not letting the correct power out of the coil. I would advise you to pick up a coil wire, clean up the contact on the coil and see if that fixes your problem.

Peace!
-mj

WheelmanZ28

I had a similar problem where i would lose power from 5600 to 6200. It turns out I had a slipping trans that was basically just reving my engine into the shift. After i put in my race-built trans, i had my consistant powerband back.

zx1216

Well this also happend to me at the track(felt like i hit the rev limiter at 5k) and it resulted in me runing a 15.2 I knew that my car was pulling like 7-10* timing throughout the run. i got a lt4 km and the car pulls all the way to redine now and only pulls about 1 deg at the most. See if you can scan your car sometime and see if its pulling timing.

Brandon 95 Z28

Make sure you try just replacing the coil wire first. I had the exact same problem and so did my friend, and for both of us it was just the coil wire.
Brandon

KGRESOCK

Madwolf,
Would you please elaborate on your statement.
Thanks
Kevin

iCE

I am pretty sure it is NOT the opti because I had mine replaced 1.5 years ago. I am gonna go and try the coil wire. I will let everyone know how it turns out. How much do they run???

slowpoke96z28

check for loose PCM grounds.

MJ_Z28

Not entirely sure...but they're cheap.

-mj